Photo-mechanical printing-plate



(MOde'L) J H. WHITLEY. Photo Mechanical Printing Plate.

Patented July13,1880.

UNITED STATES PATENT O FICE.

JOHN HLWHITLEY, OF ELMIRA, NEW YORK.

PHOTO-MECHANICAL PRINTING-PLATE.

SPECIFICATION forming part of Letters Patent No. 229,930, dated July 13, 1880.

Application filed May 7, 1880. (Specimens) To all whom it may concern:

Be it known that I, JOHN H. WHITLEY, of Elmira, Ghemung county, New York, have invented an Improvement in Plates for Photo- Mechanical Printing, of which the following is a specification.

The object of my invention is a plate intended for use in what is known as photomechanical printing, the said plate consisting of a sheet of glass or porcelain or other suitable material and certain films of such a character as to insure the adhesion of the gelatine during the inking and printing under pressure.

As is well known, it has always been a matter of difficulty to secure the gelatine printing-film to the glass or other backin g in such a manner as will prevent its displacement by the suction of the roller in inking and under the heavy pressure to which the plate is sub- 2o jected in mechanical printing. To avoid this difficnlty I interpose between the glass plate A and the gelatine film a two films, b c, the first being formed by oxidizing alcohol by chromic acid or other equivalent substance, as ferric acid 'or man ganic acid, which will, when the liquid is poured on the plate and evaporated, form a film insoluble in alcohol or water, and will adhere tenaciously both to the plate and to the superposed film. A good proportion 30 is about two and one-half grains of acid to ing-plate which will maintain its inlegrity during inking and under the heavy pressure to which'it is subjected in the process of mechanical printing.

I claim- A plate for photomechanical printing, consisting of the backing-plate A, sensitized gelatine surface film-a, and the interposed films I) and 0, formed substantially as described, and for the purpose set forth.

In testimony whereof I have signed my name to this specification in the presence of 5 5 two subscribing witnesses.

JOHN H. WHITLEY. Witnesses:

N. P. FASSETT, F. A. THOMPSON. 

